The ‘Perch Hill’ Dahlia produces blooms that emerge with a smoky crimson-pink-orange hue, softening to a sepia pink as the season progresses. These robust plants typically reach three to four feet in height, supporting four-inch diameter flowers on sturdy stems, making them excellent for cutting gardens. Successful cultivation requires attention to specific environmental conditions and ongoing maintenance. This guide details the strategy necessary to enjoy the dahlia’s abundant summer and autumn display.
Site Selection and Initial Planting
Dahlias require full sunlight for the majority of the day, meaning at least six to eight hours of direct sun exposure daily. The soil must be well-draining, as tubers are highly susceptible to rot in waterlogged conditions.
Before planting, loosen the soil to a depth of about 12 inches and incorporate organic matter, such as compost or aged manure, to improve fertility and drainage. Dahlias thrive in a slightly acidic to neutral pH environment. Adding grit can be beneficial in heavy clay soils to ensure adequate water movement.
Planting should only occur after the final spring frost has passed and the soil temperature has warmed to at least 60°F (15°C). Position the tuber three to six inches below the soil surface, ensuring the residual stem, or “eye,” is facing upward.
Space the tubers approximately 12 to 18 inches apart to allow for proper air circulation and growth. After covering the tuber, press the soil firmly and water thoroughly once. Do not water again until the first green sprouts emerge, as overwatering at this stage can cause tuber failure.
Mid-Season Maintenance and Structural Support
Once the plant is actively growing, a consistent watering routine is necessary, especially in mid-summer. Provide deep watering once or twice per week, allowing the top inch of soil to dry out between applications. This prevents the foliage from staying overly wet, which can invite disease, and encourages the development of a strong, deep root system.
Dahlias benefit from regular fertilization throughout the growing season, typically until early September. They require a balanced, low-nitrogen fertilizer, as excessive nitrogen promotes leafy growth over flower production. Apply a fertilizer with a ratio such as 5-10-10 or 10-20-20 every three to four weeks to support bloom development.
Given the ‘Perch Hill’ Dahlia’s three to four-foot height and large blooms, structural support is highly recommended. Insert a sturdy stake into the ground at the time of planting to avoid damaging the tuber later. As the stem grows, secure it loosely to the stake every few weeks with soft ties to prevent the stem from snapping during strong winds or rain.
Maximizing Blooms and Managing Pests
To maximize blooms, employ “pinching” when the young plant reaches about 12 inches in height and has developed at least four sets of true leaves. Pinch off the central growing tip just above the second or third set of leaves. This encourages the plant to branch out laterally, resulting in a bushier habit and more flower stems.
Regular deadheading of spent flowers signals the plant to continue producing new buds. Identify a spent bloom and trim the stem with clean shears just above a leaf joint where a new pair of leaves or a new shoot is emerging. Cutting at this point encourages fresh growth and maintains a tidy appearance.
Monitor the foliage and stems for pests like aphids, earwigs, and slugs, which damage new growth and buds. A strong jet of water can dislodge aphids, while slugs and snails are managed with bait or physical barriers. To prevent fungal issues like powdery mildew, ensure good air circulation and always water at the base of the plant to keep the foliage dry.
Preparing for Dormancy and Storage
In regions where winter temperatures drop below freezing, Dahlia tubers must be lifted and stored. The signal for dormancy is the first frost, which causes the foliage to turn black. Wait a few days after this frost before cutting the stems back, leaving a stub of two to four inches above the soil line.
Carefully dig around the perimeter of the plant, lifting the tuber clump from the soil without damaging the fragile neck. Shake off large clumps of soil and allow the tubers to dry, or “cure,” in a cool, dark, and frost-free location for a few days. Curing allows the skin to toughen slightly, aiding in preservation.
Once cured, clean any remaining soil from the tubers and store them in a ventilated container, such as a cardboard box or crate. Nest the tubers in a dry medium like peat moss, wood shavings, or vermiculite, ensuring they do not touch each other. Optimal storage conditions involve a consistent temperature between 40°F and 50°F and a slightly humid environment during storage to prevent shriveling.
Check the stored tubers periodically throughout the winter for signs of rot or excessive drying. If they appear shriveled, lightly misting the storage medium can reintroduce moisture. Any soft or rotten tubers should be removed immediately to prevent the spread of decay. Replant the healthy, stored tubers the following spring after the last frost.